The present invention generally relates to a novel vise structure for positioning and holding parts that need to be held in position, for example, for a machining operation, including but not limited to a micromilling operation associated with a rapid prototyping process.
It is to be understood that the vice structure of the present invention is not restricted to such applications. To the contrary, the vice structure of the present invention can be implemented in association with any mechanical, laser, water jet, or other machining process involving the temporary holding in position of a workpiece in a nondestructive manner. The vice structure of the present invention can further be implemented for reversibly holding a workpiece in position, for use in a manufacturing or an assembly process.
In general, the present application will make reference to a rapid proto typing process which is known by the name “STRATOCONCEPTION” (a registered trademark), and which is disclosed, for example, in the commonly owned European Patent No. 0 585 502-B1. Reference will also be made to the commonly owned French Patent Applications No. 98 14687 and No. 98 14688.
In general, the “STRATOCONCEPTION” process can be used to produce mechanical parts and items, particularly prototypes, from a specific computer-aided design. This is achieved by the successive steps of performing a virtual breakdown of the part to be produced into elementary laminates, placed in an array, manufacturing a plurality of elementary laminates or layers, building up the plurality of manufactured layers, and assembling the layers to form the part to be produced. The laminates originate from a prior break-down of the part on predetermined planes, and in one or more determined steps.
The underlying principle is that the volume of the part to be reproduced, as a prototype, is broken down into a multitude of laminates. The laminates are produced by machining, for example, by the rapid micromilling of a material in plate or sheet form. The materialto be used can, for example, be made of wood, a composite, plastic or metal.
The laminate that is to be machined can be held in place in several ways. Mechanical systems operating on a vacuum, or alternatively, the freezing of a thin film of water or the use of sticky tape, have been proposed and used.
While, in most cases, these systems are satisfactory, they are not truly universal, particularly for small and/or perforated parts. For mechanical holding systems, it is also necessary to perform handling operations which are prejudicial to the economy of the process. Furthermore, such processing currently entails the use of expensive consumable materials. In addition, during some machining operations, problems associated with overthicknesses of the holding material are encountered. Finally, the problem of cleaning the parts has not been satisfactorily solved.
There is, therefore, a need for a vise structure which does not exhibit the drawbacks of the prior devices.